Patent GB-1039641-A (GB)
Title: Improvements in or relating to typewriting and like machines
Inventor: PATEMAN ARTHUR BOTT
IPC: B41J33/18
Filed: 1961-09-12
Abstract: 1,039,641. Typewriters. IMPERIAL TYPEWRITER CO. Ltd., A. B. PATEMAN, and S. A. LEEDHAM. Sept. 11, 1962 [Sept. 12, 1961], No. 32779/61. Heading B6F. A typewriter has mounted on the platen carriage 12, two carriers 23a, 23b for the take-up and supply spools 24, 25, respectively, of an ink-ribbon 81, means being provided for guiding the ribbon towards and along the front of the platen which means includes a pair of guides 71, 72 carried by a member 36 which is movable parallel to the carriage movement and relative to the base and the carriage. The machine has the usual ink-ribbon mechanism 16, 17, and the additional ribbon 81 is provided for making hectograph masters. The member 36 is attached to a rack 37, Fig. 4, and is slidably mounted on the carriage. The rack 37 engages a pinion 53, Fig. 5, rotatable on a vertical spindle 41 mounted on a rearward extension 22 of the carriage 12 and having fixed thereto a pinion 54 having twice the number of teeth of the pinion 53, and a ratchet wheel 56. The pinion 54 engages a rack 34, Fig. 4, fixed to the typewriter base 11. Engaging the ratchet wheel 56 is a pawl 58 on a disc 59 rotatable about the spindle 41. A further disc 65, also rotatable about the spindle 41, is caused to rotate with the disc 59 by means of a pin 66 and is pressed by a spring 97 against an oiled felt pad situated between it and a disc 62 fixed to the spindle 41, the parts 62, 64, 65, 97 forming a slipping clutch. A gear 45 on the spindle 41 is coupled by gearing 67, 68 to a gear on the spindle 27 of the take-up spool 24. A unidirectional clamp 87, Fig. 1, on the carriage and comprising a pad 89 and a spring-urged lever 88 engages the ribbon 81 to prevent backward movement thereof, a light friction brake engages the supply spool carrier, and a pawl 30, Fig. 4, allows movement of the spindle 27 of the take-up spool in the take-up direction only. During typing movement of the carriage the gear 54 is rotated by its engagement with rack 34, and thus rotates the gear 53 and moves the rack 37 and the member 36 with the guides 71, 72. Because of the 2 to 1 tooth ratio of the pinions 53, 54 the member 36 moves to the left, Fig. 1, at 1¢ times the speed of the carriage and thus the guides 71, 72 move to the left relatively to guides 73, 75, 74 and 76. The rotation of the pinion 54 also causes a torque to be applied to the take-up spindle 27 through pawl 58, clutch 62, 64, 65, spindle 41, and gearing 45, 67, 68, and thus the slack in the ribbon created between the guides 71, 73, 75 is taken up. Since clamp 87 prevents backward movement of the ribbon the movement of guide 72 relative to guides 74, 76 causes ribbon to be drawn off the supply spool. The stretch of ribbon in front of the platen and between guides 77, 78, however, remains stationary relatively to the carriage 12 during typing. During carriage return, the pawl 58 idles so that there is no drive applied to the take-up spindle 27 and the ribbon remains stationary adjacent to the type-bar fork 18 due to the movement of guides 71, 72 relatively to the carriage. To maintain the ribbon stationary adjacent to the fork 18 during tabulation or manual movement of the carriage to the left, operation of the rack-release lever 19 or the tabulator causes, through a linkage 82, 83, 84, Fig. 1, brakes 85, 86 (Fig. 3, not shown), to be applied to both spool carriers to prevent rotation thereof, and a finger 91, Fig. 1, is operated to release the clamp 87.